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选择高含氧量、中等变质程度的神木煤制备煤基固体酸催化剂,以棕榈油脱酸、脱臭馏出物为原料进行甲酯化反应,通过正交实验研究了催化剂用量、甲醇量、反应时间、反应温度对酯化反应的影响并优化了反应条件。结果表明,煤基固体酸催化剂催化效果明显好于浓硫酸,催化剂用量和反应时间对游离脂肪酸酯化率有十分显著的影响,在最佳反应条件下酯化率可达94.70%;催化剂中所含的-OH等极性基团以及-CH3等疏水的烷基侧链使得其与甲醇和油都能良好接触,并且其结构中的-O-,-CH2-等桥键可增加碳骨架的灵活度,降低空间位阻,增加磺酸基的可及性,较大程度地提高了其催化活性。经过变质作用的烟煤自身结构较稳定,由其碳化制得煤基固体酸的结构更加稳定,在酯化反应中表现出了非常好的重复利用性。
The coal-based solid acid catalyst was prepared by Shenmu coal with high oxygen content and medium metamorphism degree. Methyl esterification reaction was carried out with deacidification and deodorization of palm oil as raw materials. The effects of catalyst dosage, methanol amount, reaction time Time, reaction temperature on the esterification reaction and optimize the reaction conditions. The results show that the catalytic effect of coal-based solid acid catalyst is better than that of concentrated sulfuric acid. The amount of catalyst and reaction time have a very significant effect on the esterification rate of free fatty acid. Under the optimal reaction conditions, the esterification rate can reach 94.70% The polar groups such as -OH and the hydrophobic alkyl side chains such as -CH3 are contained so that they are in good contact with methanol and oil and the bridge such as -O- and -CH2- in the structure may increase the carbon skeleton Flexibility, reduce steric hindrance, increase the availability of sulfonic acid groups, to a greater extent to improve its catalytic activity. The metamorphic bituminous coal itself is relatively stable in structure, and the carbon-based coal-based solid acid has a more stable structure and shows very good reutilization in the esterification reaction.